Salesforce Updated JavaScript-Developer-I Exam Questions and Answers by harlen

We must track synchronous code, setTimeout callbacks (macrotasks), and Promise rejection handling (microtasks).

Step-by-step:

Synchronous code first:

Line 01–03: Schedules a timeout at 1100 ms: logs 1 (later).

Line 04: console.log(2); → logs 2.

Lines 05–09: Construct a new Promise.

The executor runs immediately.

Inside it, another setTimeout is set for 1000 ms:

setTimeout(() = > {

reject(console.log(3));

}, 1000);

Line 09–11: .catch(() = > { console.log(4); }) attached to the promise.

Line 12: console.log(5); → logs 5.

So after all synchronous code, the console has:

2

5

At 1000 ms: inner setTimeout fires

The callback:

() = > {

reject(console.log(3));

}

Inside:

console.log(3) runs first , logging 3.

console.log(3) returns undefined.

Then reject(undefined) is called.

So at about 1000 ms, we log:

3

When the promise is rejected:

The .catch handler is scheduled as a microtask .

After the current macrotask (the timeout callback) completes, the microtask queue runs.

Thus .catch(() = > { console.log(4); }) runs shortly after, in the same 1000 ms tick.

So immediately after 3, the catch handler logs:

4

Now the logs in order are:

2

5

3

4

At 1100 ms: outer setTimeout fires

The callback from line 01 runs:

console.log(1);

Logs: 1.

Final log order:

2 (line 4, sync)

5 (line 12, sync)

3 (1000 ms timeout, then inside logs before reject)

4 (promise catch microtask after rejection)

1 (1100 ms timeout)

Concatenated: 25341.

Therefore, the correct option is:

Answer: A

Study Guide / Concept References (no links):

Event loop: call stack, macrotask queue (timers), microtask queue (promises)

setTimeout scheduling and ordering

Promise rejection, .catch, and microtasks

Evaluation order of function arguments (reject(console.log(3)))

In JavaScript, when calling a constructor function without new:

const m = Monster();

the following happens:

The function executes as a normal function , not as a constructor.

Inside a regular function (in non-strict mode), this refers to the global object :

In a browser: window

So the line:

this.name = ' hello ' ;

becomes:

window.name = ' hello ' ;

Since Monster() does not return anything, its return value is undefined:

const m = undefined;

Therefore:

m is undefined

window.name becomes " hello "

This matches option B .

JavaScript Knowledge References (text-only)

Calling a function without new uses the global object as this in non-strict mode.

Constructor functions must use new to create a new object.

Functions without an explicit return return undefined.

Key points:

Function declarations are hoisted (their definitions are available before the line where they appear).

Function expressions assigned to const or let are not hoisted as callable functions, but here anotherFlag is only used after it is defined.

Step-by-step:

flag(); at the top:

flag is a function declaration defined later; due to hoisting, it is available.

It logs ' flag ' .

The declaration:

function flag() {

console.log( ' flag ' );

}

is already in effect (hoisted before execution).

const anotherFlag = () = > { console.log( ' another flag ' ); } defines anotherFlag as an arrow function.

anotherFlag(); is called after its definition; this is valid and logs ' another flag ' .

No errors occur. The console output is:

flag

another flag

So option D is correct.

Concepts: function hoisting, difference between function declarations and function expressions, execution order.

To select an element by ID, JavaScript uses:

document.getElementById( " status " )

The ID must be passed without any selector prefixes (no dot, no hash).

Then, to update the text inside:

element.innerHTML = ' Completed ' ;

Why the others are wrong:

A uses " .status " which would match a CSS class, not an ID.

B incorrectly prepends #, which is used in CSS selectors but not in getElementById.

D attempts to use .Value with capital V, which is incorrect for DOM text; .value only applies to form elements.

Thus, option C is correct.

JavaScript Knowledge References (text-only)

getElementById takes a raw ID string with no prefixes.

innerHTML updates an element’s displayed HTML content.

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